EFFECT OF HEARTMATE LEFT-VENTRICULAR ASSIST DEVICE ON CARDIAC AUTONOMIC NERVOUS ACTIVITY

Background. Clinical performance of a left ventricular assist device i s assessed via hemodynamic parameters and end-organ function. This stu dy examined effect of a left ventricular assist device on human neurop hysiology. Methods. This study evaluated the time course change of car diac autonomic activity of 3 patients during support with a left ventr icular assist device before cardiac transplantation. Cardiac autonomic activity was determined by power spectral analysis of short-term hear t rate variability. The heart rate variability before cardiac transpla ntation tvas compared with that on the day before left ventricular ass ist device implantation. Results. The standard deviation of the mean o f the R-R intervals of the electrocardiogram, an index of vagal activi ty, increased to 27 +/- 7 ms from 8 +/- 0.6 ms. The modulus of power s pectral components increased. Low frequency (sympathetic activity) and high frequency power (vagal activity) increased by a mean of 9 and 22 times of each baseline value (low frequency power, 5.2 +/- 3.0 ms(2); high frequency power, 2.1 +/- 0.7 ms(2)). The low over high frequency power ratio decreased substantially, indicating an improvement of car diac sympatho-vagal balance. Conclusions. The study results suggest th at left ventricular assist device support before cardiac transplantati on may exert a favorable effect on cardiac autonomic control in patien ts with severe heart failure.